Click to follow and don’t get lost ↑ ↑ Popularize scientific knowledge and spread scientific psychotherapy sarcopenia is a syndrome characterized by progressive and extensive skeletal muscle content and hypofunction as its main characteristics. It is estimated that about 50 milli

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Sarcopenia is a syndrome characterized by progressive and extensive skeletal muscle content and hypofunction as its main characteristics. It is estimated that about 50 million people worldwide suffer from sarcopenia, and by 2050, the number of cases of sarcopenia is expected to reach 500 million. The prevalence of sarcopenia increases with age, and the prevalence in men is slightly higher than that in women. It is mainly manifested in clinical manifestations of body movement dysfunction, which in turn increases the risk of falls, fractures and death.

In this article, we will introduce the factors of sarcopenia, disease diagnosis and evaluation, nutritional treatment, and oral nutritional supplement treatment of sarcopenia combined with some common diseases .

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The pathogenesis of sarcopenia

The pathogenesis of sarcopenia is not fully defined. In clinical practice, primary sarcopenia caused by increased age of . Secondary sarcopenia caused by other diseases can also be seen, such as long-term restriction of activity, bedridden muscle , sarcopenia caused by factors such as sarcopenia caused by skeletal muscle denervation, severe malnutrition, tumor cachexia, endocrine metabolic diseases, and genetic . Among them, malnutrition is one of the main causes of sarcopenia.

Diagnosis and evaluation of sarcopenia

. Self-screening

self-screening methods for sarcopenia include SARC-F [including muscle strength (S), assisted walking (A), standing (R), climbing stairs (C), falling (F)] and SARC-CalF (SARC-F combined with calf circumference).

SARC-F: This scale is closely related to the patient's functional status, including 5 evaluation contents, with a score range of 0 to 10 points. The higher the score of , the higher the risk of sarcopenia. The total score ≥4 points is positive for screening. has low sensitivity but high specificity, and can accurately identify impaired physical function. It is a simple, fast and effective screening tool.

▲Simple Five-Order Score SARC‑F Questionnaire Scale (Picture Source: Reference Materials [1])

SARC-CalF: The score range of is 0~20 points, and the score of ≥11 is positive. SARC-CalF questionnaire is recommended for elderly people in the community who are ≥60 years old to use . The calf circumference is added to SARC-CalF, which improves sensitivity.

Asian Sarcopenia Working Group (AWGS) 2019 recommends to use a calf circumference or SARC-F or SARC-CalF questionnaire for screening. calf circumference value is: male <34>

. Clinical diagnostic parameters

Currently, the main parameters that can be used to diagnose and evaluate sarcopenia include muscular mass , muscle strength, muscle mass and somatic function , where the decline in skeletal muscle muscle mass is the basic symptom.

• muscle volume refers to the total number of skeletal muscles in the human body. skeletal muscle mass (ASM) of the limbs is a key indicator for evaluating muscle mass. dual energy X-ray absorption method (DXA) is the gold standard for its measurement;
• Muscle strength refers to the maximum strength that one or more muscle groups can produce. Currently, the most commonly used indicators for evaluating muscle strength are upper limb grip strength; knee flexion and extension strength is the most accurate method to evaluate lower limb muscle strength. 5 sitting-up test can be used as its simple alternative method;
• muscle mass refers to the maximum strength that can be produced by each unit of muscle. Currently, muscle structure and the degree of fat infiltration in muscles are commonly used to evaluate it. There is no recognized gold standard for measuring;
• somatic function refers to the systemic somatic function that can be objectively measured. step speed is the easiest way to evaluate physical function, while Simple Physical Status Scale (SPPB), Stand-Walking Timer Test (TUG) and Long-distance Walking are indicators for evaluating physical function more comprehensively. Sarcopenia can only be diagnosed when patients with muscle strength or physical function decreases; if they are combined with muscle strength and physical function decreases, they can only be diagnosed as sarcopenia; if they are combined with muscle strength and physical function decreases, they can only be diagnosed as severe sarcopenia.

  Nutritional treatment for sarcopenia

  Malnutrition is an important cause of sarcopenia and the main aspect of disease intervention. Nursing staff can guide and urge patients to undergo diversified and adequate nutritional supplements according to the patient's own nutritional needs, such as encouraging patients to eat foods rich in animal protein , amino acid , carnitine , ω-3 polyunsaturated fatty acids, micronutrients, etc. for a long time.

. Protein

Supplementation of protein can promote muscle protein synthesis and has a dose-effect relationship. studies have shown that legumes and dairy products have better effects in skeletal muscle maintenance and strengthening, but the latter has greater and stronger effects.

In terms of maintaining muscles and promoting muscle protein synthesis: whey protein is better than casein , and milk protein is better than soy protein. The enteral nutritional preparation whey protein powder combined with whole protein (whey protein isolate) and proteolyte (hydrolyzed whey protein) may be more beneficial for inducing muscle protein synthesis.

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. Amino acid

Related systematic reviews point out that although protein supplementation alone has a good nutritional effect, when amino acid supplementation is combined, the patient's muscle strength and physical mobility will be better. leucine is considered to be the most effective stimulator of protein synthesis, and creatine and β-hydroxy-β-methylbutyrate (HMB) complexes can also be selected.

• phosphocreatine is a form of energy reserve in skeletal muscle, and supplementing creatine has an improved effect on sarcopenia.
• HMB is a natural product produced during the metabolism of leucine in essential amino acids . Its can promote protein conversion, reduce protein decomposition and enhance muscle regeneration ability. HMB supplement can increase the patient's muscle mass.

It is recommended to supplement leucine alone to increase the patient's muscle mass. It is recommended that the patient's minimum leucine intake is 55 mg/(kg·d).

. Carnitine

Carnitine is an essential nutrient for metabolizing long-chain fatty acids in the body, especially in muscles. A multi-center, double-blind randomized controlled study of 72 patients with advanced pancreatic cancer with an average weight loss of 12.0 kg ± 2.5 kg showed that 4 g carnitine was intervened every day for 12 weeks, and the intervention group's body mass index (BMI) increased by 3.4% ± 1.4%, and its nutritional status (somatic cell mass, body fat) improved.

. ω‑3 polyunsaturated fatty acids

ω‑3 polyunsaturated fatty acids have the effect of promoting skeletal muscle anogenesis. supplementation with ω‑3 polyunsaturated fatty acid can help prevent and treat tumor-related sarcopenia. If nutrients rich in protein and energy are used in combination, the increase of lean body tissue can be obtained, thereby gaining weight and delaying the loss of muscle tissue in the patient.

5. Micronutrients

Micronutrient intake also needs attention. Magnesium plays an important role in the normal function of human muscles and metabolism, and also affects the synthesis of proteins. magnesium intake is significantly associated with sarcopenia. study pointed out that compared with non-sarcopenia people, sarcopenia people have lower magnesium intake, so recommends that patients consume foods with high magnesium content, such as dark green vegetables, coarse grains and nuts.

Vitamin D is an important factor in regulating the balance of calcium, phosphorus and bone metabolism. It is very important for bone health and also has a potentially important role in muscle health. Reduced vitamin D is associated with decreased muscle function and increased disability. However, the effect of supplementing vitamin D alone is limited, and it is necessary to supplement with other nutrients such as protein to achieve better results.

According to the recommendation of the "Chinese Expert Consensus on Nutrition and Exercise Intervention in Muscle Attenuation Syndrome", the supplementary dose of vitamin D in patients with sarcopenia is 15 μg/d ~20 μg/d.

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Sarcopenia combined with some common diseases oral nutritional supplement treatment

At present, a variety of chronic diseases are closely related to the occurrence of sarcopenia, including:

May cause malnutrition malnutrition The underlying diseases, such as heart failure , chronic obstructive pulmonary disease , chronic renal failure , etc.; the underlying diseases that lead to limited mobility of the body, such as severe obesity, falls, bedridden, chronic arthritis , etc.; the underlying diseases that lead to muscle loss, such as diabetes , metabolic syndrome, thyroid dysfunction , etc. We share some of the diseases, as follows:

• sarcopenia combined with diabetes

diabetic patients often have insulin resistance, chronic inflammation, mitochondrial dysfunction, neurovascular system complications, poor blood sugar control and long-term medication use, which is closely related to sarcopenia. patients with sarcopenia and diabetes can use a special formula for diabetes that has a small impact on blood sugar.

• sarcopenia combined with malignant tumors

malignant tumors are chronic wasting diseases. Patients often show progressive decline in lean body mass, decreased muscle strength, and decreased muscle function. Patients with sarcopenia who are malignant tumors with can choose treatments with high fat, low carbohydrate content, and rich in omega-3 fatty acids.

• Sarcopenia combined with other diseases